Spring construction for furniture



Sept. 6, 1955 s. s. JONAS 2,717,029

SPRING CONSTRUCTION FOR FURNITURE Filed June 20, 1952 3 Sheets-Sheet l @u Uyl-QQ Sept. 6, 1955 s. s. JoNAs 2,717,029

SPRING CONSTRUCTION FOR FURNITURE Filed June 20, 1952 5 Sheets-Sheet 2 Sept. 6, 1955 s. s. JONAS SPRING CONSTRUCTION FOR FURNITURE 5 Sheets-Sheet 5 Filed June 20, 1952 fvvf/vrok: 5A Ml/EL 5. fo/VAS a7 HIS A 7 701e/VE7S www5/745e@ F0575? @FM4/ams United States Patent() This invention relates to spring constructions for furniture and, more particularly, to a spring suspension system for various articles of furniture which incorporates adjustment means to facilitate maintaining the spring suspension of a piece of furniture in a condition of optimum adjustment.

One of the recurring problems encountered in the use of upholstered articles of furniture such as chairs, divans, mattresses and similar articles which incorporate spring supporting structures, is the ultimate subsidence of the upper surfaces of such articles of furniture which materially reduces the comfort experienced when the article of furniture was new and which is the criterion of the eventual failure of the furniture to provide adequate support.

I have discovered that the major portion of such subsidence is due to the compression of the upholstery wadding and the setting of the foundation springs which ultimately result in substantial subsidence of the upper surface of the upholstered piece of furniture. For instance,

the cotton batting, horsehair, or other upholstery ller conventionally utilized, will frequently be compressed as much as one inch after relatively short periods of use of upholstered furniture. Furthermore, an eight-inch foundation spring will set by as much as one-half an inch during a similar period of time. During `the same period, relatively slight stretch or give will be encountered in the supporting webbing or in the canvas sheet or sheets formed of other material.

It is, therefore, an object of my invention to provide a spring construction for articles of furniture which is so constructed that it can accommodate the subsidence of the upper surface of upholstered articles of furniture attributable to spring set and compression or wadding of the upholstery filler utilized. Although I will describe my invention as applied to an article of furniture such as a sofa or divan, I do not intend to limit the practice of my invention, or the application thereof, to such particular article of furniture since it is conceivable that the principles of my invention can be applied with equal success to chairs, mattresses, and other articles of furniture incorporating spring structures in their constructions.

As a result of my study of the problem of subsidence of the upper surface of upholstered furniture, I have come to the conclusion that the major factor causing such subsidence is the vertical wadding of the upholstery filler and the vertical set of the bank of foundation springs utilized in such furniture, and it is another object of my invention to provide a spring supporting structure which is adjustable in a vertical direction to compensate for such subsidence.

It is an additional object of my invention to provide a spring seat supporting construction which is designed with adjustment means incorporated therein which is capable of vertically lifting the supporting web or sheet immediately upon the completion of the article of furniture and which can, therefore, be adjusted to overcome initial defect resulting from structural failures during the manufacturing process.

A further object of my invention is the provision of a spring construction for articlesr of furniture which includes a frame having supported thereupon a foundation spring supporting unit whichis capable of being vertically shifted in the frame by adjusting means secured between the frame and the supporting unit, the vertical movement of the unit, as a body, accomplishing the vertical shifting, as a body, of a bank of foundation springs disposed thereupon .so that subsidence of the upper surface of the upholstered furniture, due to the wadding of the filler material or spring set in the foundation springs, may be readily overcome despite the fact that the supporting webbing or sheet has not sagged or stretched to any appreciable extent.

A further object of my invention is the provision of a spring construction of the aforementioned character in which the foundation springs are divided into first and second banks, the first bank being secured on the upper surface of the frame of the article of furniture and the second bank being bodily disposed upon a spring supporting unit which is shiftable with respect to the frame of the article of furniture in a substantially vertical path.

Other objects and advantages of my invention will be apparent from the following specification and the accompanying drawings, which are for the purpose of illustration only, in which:

Fig. l is a perspective view of a divan or sofa incorporating the spring construction of my invention;

Fig. 2 is a bottom planview taken in the direction of the arrow 2 of Fig. 1;

Fig. 3 is a transverse, enlarged, partly sectional view takenon the broken line 3-3 of Fig. 2;

Fig. 4 is an enlarged, fragmentary, partly sectional view showing a detail of `the spring construction of my invention;

Fig. 5 is a fragmentary plan view taken in the direction of the broken line 5--5 of Fig. 4;

Fig. 6 is a partly sectional view of an alternative embodiment of the spring construction of my invention;

Fig'. 7 is a fragmentary view taken in the direction of the arrow 7 of Fig. 6;

Fig. 8 is a transverse, partly sectional view of an alternative embodiment of the spring construction of my invention; and

Fig. 9 is a bottom plan view taken in the direction of the arrow 9 of Fig. 8.

Referring to the drawings and particularly to Figs. l5 thereof, I show a sofa 10 of conventional tight seat construction, that is, wherein no separate seat cushions are provided but wherein the seating surface 11 constitutes an integral portion of the sofa construction and is not separable from the construction as when separate cushions are provided as a seating surface. The base 13 of the sofa 10 includes a substantially rectangular frame 15 which includes laterally spaced front andV back rails 16 and 17, respectively, which are maintained in operative relationship with each other by end rails 18 and 19. Secured to the undersides of the front and back rails 16 and 17 are feet 20 which space the frame 15 above the surface 22 upon which the sofa 10 rests.

The front and back rails 16 and 17 and the end rails 18 and 19 define a rectangular opening 24 for the reception of a portion of the spring construction 25 which is the subject matter of my invention. Fastened to the upper surface 27, as by means of screws 28, is a plurality occurring of brackets each of which includes an integral, angularly and upwardly directed arm 31v which projects inwardly a substantial distance beyond the edge of the opening 24, as defined by the inner edge of the back rail 17, to provide a support for an adjustment means,

indicated generally at 35, a substantial distance above the lower edge of the opening 24.

The adjustment means 35 includes an elongated bolt 36 which is non-rotatably mounted in a rectangular opening 37 in the arm 31 at its upper end and which has threadedly engaged upon its lower end a wing nut 38. Encompassing the lower end lof the shank of the bolt 36 and having its lowermost end seated upon the wing nut 38 is acompressi'on spring 39.

A plurality of brackets 41 is secured to the upper surface of the front rail 16, each of the brackets being provided with an opening 42 for receiving the upper end of a tension spring 43. It will be noted that the adjustment means 35 and the tension springs 43 are disposed at spaced intervals along the length of the front and back rails 16 and 17'and opposite one another to support a foundation spring supporting unit 45 constituted by an elongated rectangular sheet of canvas 47 for movement in a substantially vertical path x-x, best shown in Fig. 4, in the opening 24.

An elongated reinforcing strap 49 is located in a pocket 56 in the longitudinal edge of the supporting unit 45 disposed adjacent the inner edge of the back rail 17. A plurality of spaced openings 51 is formed in the strap 49 opposite contiguous openings in the pocket 50 for the reception of the lower ends of the Shanks of the bolts 36. As best shown in Fig. 4 of the drawings, the shank of cach bolt 36 is inserted in an opening 51 in the strap 49 and the upper end of each `spring 39 is seated against the underside of the pocket 50, the wing nut 38 being threadedly engaged upon the lowermost end of the shank of the bolt 36 and serving as the bottom seat for the compression spring 39.

It will be noted that the included angle b between a vertical plane A-A and the longitudinal axis B-B of the bolt 36 is substantially less than 60 so that the major component of movement of the lateral edge of the supporting unit 45, as caused by the upward threading of the wing nut 3S on the shank of the bolt 36, will be in a vertical direction with a relatively slight lateral component in the direction of the back rail 17. Therefore, the foundation spring supporting unit 4S will be carried upwardly in a substantially vertical path x--x by the rtation of the wing nuts 38 on the shanks of the bolts 36 and a relatively small component of lateral movement will serve to tension the spring supporting unit 45 to adjust for any possible stretching which may have occurred in Said unit.

The lowermost ends of the tension springs 43 pass through longitudinally spaced openings in an elongated pocket 53 provided in the lateral longitudinal edge of the spring supporting unit 45 adjacent the inner edge of the front rail 16, a stiffening bar or wire 55 being dis posed in said pocket and adapted to support any loads imposed upon the edge of the spring supporting unit 45 through the tension springs 43. Although, in the presently discussed embodiment of my invention, I show the adjustment means 35 connected to one rail of the sofa 10 and the tension springs 43 connected to the opposite rail thereof, it is intended that adjusting means 35 may be disposed on both sides of the spring supporting unit 45 if the construction of the sofa necessitates such distribution of the adjusting means. However, by providing properly calculated tension springs 43, I have discovered that a reduction in load on the lateral edge of the spring supporting unit 45 supported by the tension springs 43 occasioned by the upward movement of the lateral edge of the spring supporting unit 45 supportedby the adjust,- ment means is suicient to cause the tension spring supported edge to move upwardly` simultaneously and a substantially equivalent distance with the adjusting means supported edge of the spring supporting unit 45.

Therefore, when the adjusting wing nuts 38 are threaded upwardly on the Shanks 36, the entire spring supporting unit moves up bodily in a vertical direction along the substantially vertical path x-x and the spring supporting unit 45 is maintained in a substantially horizontal plane without any inclination of a significant nature in the upper surface thereof. This is a most important feature of my invention whose significance will become apparent with a further description of the additional features of the spring construction. It should be pointed out here that although the invention is discussed in connection with the suspension of the seating surface 11 of a sofa 10, the principles thereof have application to a wide variety of furniture constructions and it is not intended that the application of the invention to a specific piece of furniture be taken in a limiting connotation. Furthermore, although I have described the spring supporting unit 45 as a sheet 47 of canvas, it is obvious that other spring supporting units serving the same function, such as interlaced webbings, sheets of other material, and other alternative spring supporting units, may be substituted for the sheet 47 of canvas utilized in the presently discussed embodiment of my invention.

Attached to the opposite longitudinal edges of the spring supporting unit 45 are dust strips 57 whose sole purpose is the prevention of the entry of dust into the interior of the spring construction 25 and whose connection between the lateral longitudinal edges of the spring supporting unit 45 and the front and back rails 16 and 17, respectively, has absolutely no structural significance whatsoever so far as the movement and adjustment of the supporting unit 45 is concerned. The dust strips 57 may be constituted of eXtra material at the edges of the unit 45.

In the construction of my invention, as previously indicated, the major component of movement in the spring supporting unit 45 is vertical and it is possible to shift the spring supporting unit bodily in a vertical path as much as two inches, or even more if necessary, the twoinch vertical movement being accompanied by less than one inch of lateral movement of the edges of the spring supporting unit 45. Obviously, such a very large range of vertical adjustment provides a spring supporting unit which can be adjusted innumerable times during the life of the article of furniture in which the spring construction is incorporated to maintain itin optimum condition of adjustmentto secure the maximum comfort characteristics therefrom.

Supported on the upper surfaces of the front and back rails 16 and 17 and the end rails 18 and "1 9 is a first bank 60 of foundation springs 61, the springs 61 constituting the first bank 60 being disposed in vertical orientation and along the longitudinal edges of the spring construction and at the opposite ends thereof. The springs 61 constituting the first bank 60 are the shorter springs of the spring construction and are of somewhat greater stiffness than the remaining springs of the spring construction 25 to be subsequently described. Due to their increased stiffness and somewhat shorter length, the springs 61 are less subject to spring set, that is, the reduction in the length thereof occasioned by prolonged imposition of compressive loads upon the springs. Furthermore, the springs 61 are secured to the rails of the frame 15 with their top portions vertically aligned with their bases, unlike conventional edge constructions wherein the top portions of the springs are vertically misaligned with the bases thereof. This prevents failure of the springs 61 since the entire lengths of the springs support loads imposed thereupon. However, since the springs 61 are disposed at the lateral edges and the ends of the construction and the anatomy of the user of the sofa 10 does not remain in load imposing relationship upon the relatively stii springs, no discomfort results from the use thereof and the possibility of subsidence of the front and rear edges and ends of the spring construction is relatively negligible.

Disposed upon and having its lower ends supported by the spring supporting unit 45 is a second bank 65 of foundation springs 66, said springs 66 beingsubstantially` longer, by as much as two inches, than the springs 61 constituting the rst bank 60 and being more easily corn-4 pressible than the springs 6l to provide a softer seating area in those portions of the seating surface 11 which are engaged by the anatomy of the individual seated on the sofa 10. Since the springs 66 constituting the second bank 65 have their lowermost ends supported upon the bodily movable Spring supporting unit 45, they can be substantially longer than the springs 61 of the first bank 60, thus materially increasing the comfort experienced in sitting on the seating surface 11 of the sofa 10 because the comfort is proportional, to some extent, to the length of spring utilized.

Due to the length of spring and the fact that the springs 66 are more readily compressible, the rate of spring set in these springs is much more appreciable than that encountered in the springs 61 and such springs can be expected to set in a relatively short time by as much as onehalf inch. Naturally, when such set occurs, the upper ends of the springs 66 drop below the upper ends of the springs 61 and a depression or trough is formed in the seating surface.

The lower ends of the springs 61 of the first bank 60 are, of course, secured to the upper surfaces of the front and back rails 16 and 1/ and the end rails 18 and 19 by suitable means such as staples, while the lower ends of the springs 66 constituting the second bank of foundation springs 65 are secured, as by sewing or wiring, to the fabric of the sheet 47 of the spring supporting unit 45. Stretched tautly across the upper ends of the springs 61 and 66 is a web 68 of fabric such as burlap which provides a restraining and compressing means and a seat for the upper ends of said springs and which is fixedly secured by means of tacking or similar fastening expedients to the edges of the rails 16, 17, 18, and 19. Supported upon the fabric 68 and contoured in any desired fashion to provide a suitable or desired appearance is a bat 70 of upholstery filler which is covered by a covering 72 of decorative upholstery fabric which constitutes the exterior covering of the sofa and the contact surface of the seating surface 11. The upholstery filler constituting the bat 70 is, of necessity, generally formed of material such as cotton batting, horsehair, feathers, or rubberized hair and is subject to compaction after relatively short periods of use.

For instance, as a person seats himself on the seating surface 11, a sliding force in a relatively horizontal plane is encountered as he slides his posterior backwardly across the fabric 72 which ultimately causes stretching in the fabric. At the same time, the upholstery filler of the bat '70 is pressed downwardly against the spring supported web 68 of fabric and is momentarily compressed to a maximum degree by the imposition of practically all of the weight of the person seating himself thereupon. Subsequently, when finally seated, a load in a vertical plane is imposed upon the filler of the bat 70 causing the compaction of the fibers thereof which ultimately becomes permanent. Obviously, the stretching of the fabric 72 of the sofa 10 and the compaction of the filler 70 result in considerable looseness in the tight seat construction which is objectionable for various reasons, among them being the excessive wear encountered in the fabric 72 and the abrading and shredding of the upholstery filler constituting the bat 70. The seating surface 11 of the upholstered article assumes a dilapidated and unattractive appearance and purchasers of such articles frequently return them to the merchant from Whom purchased for reconstruction of the same. It is also a fact that the maintenance of a tight fabric cover will prevent undue wear in the bat 70 of filler.

As previously indicated, coupled with the stretching of the fabric 72, the compaction of the upholstery filler will cause the seating surface 11 to drop an inch or more, resulting in the creation of an unattractive trough therein. The compaction of the bat 70 and the stretching of the fabric 72 are, of course, accompanied by the set of the springs 66 of the second bank of foundation springs which may set as much as one-half inch. Therefore, the total settling of the three components of the spring construction can result in a subsidence of the seating surface 11 of as much as one and one-half inches without taking into account any stretching of the fabric of the spring supporting unit 45 which may occur.

As previously indicated, the compaction of the bat 70, the stretching of the fabric 72, and the setting of the springs 66 may occur in furniture long before the fabric of the spring supporting unit 45 has stretched or otherwise lost its tautness.

However, in the spring constructions 2S of my invention in which the spring supporting unit 45 is bodily shiftable in a primarily vertical path x-x, the initial subsidence of the seating surface 11, due to the aforementioned factors other than the stretching of the fabric of the spring supporting unit 45, can be immediately accommodated by the upward adjustment of the spring supporting unit 45 through the utilization of the adjusting means 35 to carry the spring supporting unit 45 bodily upward and also to simultaneously carry all of the springs 66 constituting the second bank 65 of foundation springs upward bodily as a unit to overcome the losses incurred by the setting of the springs 66, the compaction of the bat 70 and the looseness or stretching of the covering fabric 72.

This mode of adjustment is only possible because the v spring seat construction does not rely upon lateral adjustment or tensioning of the spring supporting unit 45 or partial raising of the sagging spring supporting unit due to the loss of tension therein or stretching thereof, but, rather, depends upon the vertical shifting of the spring supporting suit and the second bank of foundation f springs as a unit. In addition, unlike conventional spring constructions incorporating lateral adjustment features wherein the springs utilized have their bases supported in the same horizontal plane on the spring supporting unit, applicant has divided his springs of the spring construction into two banks, one of which, the second bank 65, is initially and at all times vertically movable with respect to the lirst bank 60, thus permitting initial adjustment of the spring construction 25 and adjustment throughout the life of the unit despite the fact that the fabric of the spring supporting unit has not deteriorated sufficiently to cause it to substantially stretch.

Inherent in the spring construction 25 of my invention is the provision of the greater length of springs 66 in the second'bank of foundation springs 65 which materially increases the comfort experienced when a person is seated on the seating surface because the greater length of the springs 466 permits a more comfortable ride to be achieved. The position of the springs 66 on the spring supporting unit 45 in the opening 24 provides a drop V spring construction which permits of relatively great vertical movement of two or more inches and, in addition, lateral adjustment of one or more inches.

The desirable results achieved by the incorporation of the spring construction 2S of my invention in an article of furniture are attributable, in part, to the suspension of the spring supporting unit 45 for bodily movement in a primarily vertical path and to the drop spring construction which allows ample room for vertical adjustment of the bodily movable spring supporting unit 45 and the second bank 65 of springs supported thereupon. These are most important features of my invention.

Referring to the drawings and particularly to Figs. 6 and 7 thereof, I show a spring construction 25 which is quite similar in most aspects to the previously discussed embodiment of my invention and in the description whereof like'reference numerals have been applied to like constituent elements previously discussed and described in the disclosure of the embodiment of the invention shown in Figs. l`5 of the drawings. In the embodiment under consideration, the construction of the spring construction is substantially identical with that of the previously discussed embodiment thereof. However, the spring supporting unit is provided at both edges thereof with longitudinally extending pockets into which are placed straps 49 provided with a plurality of longitudinally spaced openings 51 adapted for the reception of the Shanks of elongated bolts 75, said bolts being provided with heads 76 which have transversely inclined bores 77 provided therein. Since adjusting means 35 are provided on both of the lateral edges of the spring supporting unit 45, it is necessary to adjust the adjusting means 35 on both edges of the spring supporting unit 45 when it is desired to vertically and bodily shift the spring supporting unit 45 in the opening 24 in the frame 13.

Extending transversely of the longitudinal axis of the frame 13 and spanning the opening 24 are supporting means 78 constituted by a plurality of longitudinally spaced heavy gage wires or lightweight rods whose opposite ends are received in bores Slt provided in the front and back rails 16 and 17, respectively. The ends of the rods or wires 79 are headed or otherwise deformed, as at 82, and rest upon Washers 83 interposed between the undersides of the heads or deformed portions and the outer surfaces of the front and back rails 16 and 17. As best shown in Fig. 7 of the drawings, the heads 76, and more particularly the bores 77 thereof, receive the wires 79 and the adjusting means 35 are thus supported thereupon in spaced relation with each other. Since the bottoms of the foundation springs 66 of the second bank of foundation springs are secured to the upper surface of the unit 45 in spaced relation, they serve to maintain the spring supporting unit 45 substantially taut. However, if desired, tension springs 84, secured at their opposite ends to the heads 76 of the bolts 75 and the inner face of the front or back rail 16 or 17, can be provided to maintain the heads of said bolts in a condition of maximum spacing to resist any tendency of the heads of the bolts toward lateral movement in the direction of each other.

The supporting means 7S constituted by the Wires 79 thus support the upper ends of the adjusting means 35 a substantial distance above the lower edge of the opening 24 and also provide a relatively flexible and resilient supporting means for the adjusting means 35 and consequently for the spring supporting unit 45 and the second bank 65 of foundation springs 66 mounted thereupon. Furthermore, the transverse disposition of the Wires 79 and their securement at their opposite ends to the front or back rails of the frame 13 substantially rigidify said ,-4

frame and prevent the possibility of spreading thereof.

In addition, the suspension of the adjusting means 35 on the wires 79 permits a slight amount of lateral movement of the adjusting means 35, and thus the spring supporting unit 45, on the wires 79, permitting a certain amount of lateral movement in the entire bank 65 of foundation springs 66 and contributing to desirable riding qualities in the upholstered furniture in which the spring construction 25 is incorporated by facilitating gentle lateral movement of the second bank 65 of foundation springs 66.

In addition, the provision of the supporting means 78 simplifies, to a large extent, the suspension of the adjusting means 35 in the opening 24 since it eliminates the brackets 30 and 41 utilized to suspend the supporting means 35 and the tension springs 43 in the previously discussed embodiment of the invention. Furthermore, the installation of the adjusting means 35 is materially expedited since the necessity for securing individual adjusting means 35 to individual brackets is obviated, two adjusting means 35 being simultaneously located on a Supporting Wire 79 at the same time. Also, the elimination of the brackets, the attaching screws, and the necessity for applying them to the front and back rai-ls 16 S and 17 materially reduces the overall cost of the spring construction 25.

An alternative embodiment of the spring construction of my invention is generally indicated at in Figs. 8 and 9 of the drawings wherein those portions of the construction which are identical with previously discussed portions of the embodiment disclosed in Figs. l-S, are indicated by identical reference numerals for purposes of convenience. The adjusting means 35 and the brackets 30 therefor are mounted in substantially the same way as the adjusting means in the embodiment of Figs. l-S of the drawings, the major changes in this embodiment of the invention lying in the mode of suspension of the spring supporting unit 45 and details of the construction thereof.

The spring supporting unit 45, constituted by an elongated imperforate sheet of canvas or similar material, is provided at its opposite lateral edges with elongated pockets 92, said pockets having deposited therein edge stiffeners 9-3 constituted by elongated lengths of heavy gage wire or iight-weight rod. Provided at longitudinally spaced intervals in the pockets 92 are elongated openings 95 which expose short portions of the lengths of the edge stiffeners 93.

Mounted upon the periphery of each of the bolts 36 and supported thereupon by the compression spring 37 is an engagement member 97 which is constituted by a substantially rectangular body 98 formed of relatively heavy gage metal and provided at its innermost end with a hook-like portion 101, said body having an elongated opening 192 which permits the body 98 of the engaging member 97 to encompass the shank of the bolt 36 and to be supported thereupon. Each of the bolts 36 of the engagement means 35 supports an engagement member 97 to maintain the hook-like portion 101 thereof in supporting engagement with an edge stiftener 93, said hook-like portions 101 engaging at least a portion of the periphery of the edge stiffeners 93 at each of the elongated openings 95 in the pockets 92. Since sufficient lateral tension is constantly imposed upon the body 98 of the engagement means 97 by the upward bias of the compression springs 39, the hook-like portions 101 of the engagement means 97 are maintained in operative relationship with the portions of the peripheries of the edge stiifeners 93 after they have been engaged therewith. However, the spring supporting unit 45 can be readily removed from supporting engagement with the engagement members 97 by merely unthreading the wing nuts 38 on the bolts 36 to reduce the bias of the springs 39 against the engagement members 97`and thus to permit the edge stileners to be readily unhooked therefrom. Conversely, the spring supporting unit 45 can be readily installed on the adjusting means 35 by merely snapping the edge stiffener 93 over the hook-like portions 101 of the engagement means 97 and adjusting the tension of the compression springs 39 by the rotation of the Wing nuts 3S to retain the spring supporting unit 45 at the desired height with reference to the opening 24 in the frame 15.

Disposed between the adjusting means 35 and below the spring supporting unit 45, are lateral tensioning means 105 constituted by centrally located tension springs 106 secured by cords or Wires 107 to the Shanks of the bolts 36 of the adjusting means 35. The ends of the cords or wires 107 need not necessarily be secured to the Shanks of the bolts 36 but can be secured, if desired, to the engagement member 97 or the edge stifeners 93.

The tensioning means serve to prevent inadvertent lateral spread between the engagement means 97 and also insure, by so tensioning the engagement means 97, that the spring supporting unit 45 will always be maintained in a condition of maximum tautness. Furthermore, the tensioning means 105 serves to prevent the Shanks of the bolts 36 from upward movement in the arms 31 of the brackets30, thus insuring that the non-rotatable heads thereof are always located in the arms 31 to prevent All the rotation thereof and permit the easy adjustment of the spring supporting unit 45 by the adjustment means 35.

In order to stabilize the second bank 65 of foundation springs 66 disposed upon the upper surface of the spring supporting unit 45, longitudinal tensioning means 109 are provided which are constituted by elongated tension springs 110. As best shown in Figs. 8 and 9 of the drawings, the longitudinal tensioning means 109 is disposed with the tension springs 110 constituting the same with their longitudinal axes in substantial parallelism with the longitudinal axes of thefront and back rails 16 and 17 of the sofa 10, the coils of the tension springs 110 encompassing and joining the base coils of adjacent springs 66, as best shown in Fig. 8 of the drawings, thus maintaining the springs 66 of the second bank 65 of foundation springs in a coherent integrated unit and preventing lateral or longitudinal shifting of the springs on the spring supporting unit 45. By providing the longitudinal tensioning means 109, the second bank 65 of foundation springs 66 is materially stabilized with reference to the upper surface of the spring supporting unit 45, thus eliminating the possibility of longitudinal lateral shift of the bank 65 and preventing cocking or twisting of the springs 66 upon the spring supporting unit 45.

The provision of the lateral tensioning means 105 in conjunction with the longitudinal tensioning means 109 provides an exceptionally stable and integrated unit which is adapted to perform the manifold functions of the spring construction of my invention without any shifting or mislocation of the component parts thereof.

I thus provide by my invention a spring construction for various articles of furniture which is designed to remedy the sagging of the upholstered surfaces of furniture by compensating for subsidence of the upper surfaces due to various factors alluded to above the provision of a bodily shiftable spring supporting unit which has secured to the upper surface thereof a bank of foundation springs which is bodily shiftable as a unit on the spring supporting unit. Furthermore, by my invention I provide a drop spring construction wherein the bank of foundation springs on the spring supporting unit is disposed at a lower level than a bank of foundation springs associated therewith whereby relative adjustments between the two banks of foundation springs can be accomplished.

Furthermore, by the provision of a spring construction manufactured in accordance with my invention I eliminate dependence upon lateral adjustment of the spring supporting unit as the sole means for accommodating for subsidence of the upper surface of the upholstered article of furniture, depending primarily upon the bodily shift VYat a relatively low cost and which is readily adjusted without any tools or other appliances whatsoever.

I claim as my invention:

l. In a spring construction for furniture, the combination of: a frame including front and back rails operatively connected to each other to define an opening therebetween; a iirst foundation spring bank mounted on said rails to dene the edges of said construction; a bodily movable sheet of flexible material disposed in said opening with opposed edges thereof being spaced inwardly from said front and back rails, respectively; rigid reinforcing means extending along and secured to each of said opposed edges, each of said opposed edges being movably supported from its adjacent rail by a plurality of supporting members extending obliquely upwardly and outwardly from said reinforcing means to said rails; means for selectively and individually changing the effective length of said supporting members along at least one of said opposed edges whereby to vertically adjust said edge in said oblique direction; and a second foundation spring bank supported on said sheet of exible material for vertical movementk therewith.

2. A spring construction as defined in claim 1 including: a panel of flexible material iixed to each of said edges of said sheet of flexible material along the full length thereof, each of said panels extending loosely to the adjacent rail and being fixed thereto to function as dust seals,

.said panels extending from said edges to said rails above said supporting members.

3. A spring construction as dened in claim 1 wherein said rigid reinforcing means comprise elongated metal rods and wherein each of said supporting members comprises a bolt secured to one of said rails and extending obliquely downwardly therefrom, an element embracing the adjacent one of said metal rods, said element having an aperture receiving said bolt, and a nut on said bolt below said element.

References Cited in the le of this patent UNITED STATES PATENTS 2,113,135 Goodman Apr. 5, 1938 2,251,104 Bank July 29, 1941 2,287,030 Eaton June 23, 1942 2,327,829 Sternberg et al Aug. 24, 1943 2,417,146 Weingarten Mar. 11, 1947 

